Fumigant compositions comprising ethylene dibromide and 1, 2-dibromo-3-chloropropane



vision of a new method'and to benefit'th'e plants grown in the treated soil. practice protects 'the plants from the ravages of soildwelling invertebrate organisms' which attack their roots United States Patent OfiFice 2,849,367 Patented Aug. 26, 1958 FUMIGANT COMPOSITIONS COMPRISING ETH- YLENE DIBROMIDE AND 1,2-DlBROMO-3-CHLO= ROPROPANE Charles R. Youngson, Long Beach, and Cleve A. I. Goring, Garden Grove, -Calif., assiguors to The Dow Chemical Company, Midland, Mich., a corporation of Delaware No Drawing. Application February 1, 1957 Serial No. 637,610

9 Claims. (Cl. 167-4 19) The present invention relates to fumigant compositions and is particularly concerned with a new fumigant compositionand an agronomic practice for improving the ability of soil to support plant growth.

It is an object of the present invention to provide a new fumigant composition. A further object is to supply a new agronomic practice for improving the plant growing properties of soil and the ability of soil to support the growth of crops. Another object is the procomposition for improving the emergence, seedling'growth and the harvest of crop plants. A further object is the provision of a new method and composition for treating soil to obtain improved controls of soil-dwelling invertebrate organisms such as wire 'worms and nematodes. An additional object is the provision of a newmethod'and composition for treating soil which will accomplish thestimulation of the growth of crops. Other objects will become apparent from the following specification and claims.

The new fumigant composition of the present inventi'on comprises about one part by weight of ethylene dibromide in adr'nixture with from about threeto'te'n parts by weight of 1,2-dibromo-3-chloropropane. composition advantageously may be 1 employed in many types of fumigation-operations, self tothe tre'atment'of soil or other growth media to im- While this it conveniently adapts itprove the ability of the soil'to supportplant growth and Such and improves the growth and harvest of crop plants. It has also been found that the treatment accomplishes changes'in the soil which'stimulate the growth and improve the growthcharacteristics of crops grown therein.

It is among the'adVantageS-ofthe present invention that the toxicants in the=mixture=appear to be mutually activating so that a greater thanadditive or synergistic result is accomplished as regards the eifect on the plant growing properties of the soil and the control of insect and other undesirable organisms and particularly invertebrates such as wire worms and nematodes.

The composition 'comprising the mixture of toxicants -is suificiently increased in efiectiveness so as to permit the eifective utilization of reduced amounts of ethylene dibromide and of 1,2-dibromo-3-chloropropane and the obtaining of crop yields and controls of soil-dwelling or- .ganisms which aremuch superior to those obtained when either of the constituents of the mixture is employed alone. An additional advantage is that these reduced eifective dosages of the mixture of toxicants materially reduce the "hazards of soil residues. Thus, the practice of the presentinvention provides a very desirable economic advantage for theagriculturist.

Ethylene dibromide and 1,2-dibromo-3-chlor0propane are mobile liquids'which boilatl3l.5f C.'andl85 C. at

atmospheric pressure, respectively. Mixtures of the compounds are somewhat soluble in many organic solvents and of low solubility in water and are adapted to be 2 readily-and conveniently distributed in soil. It is among the advantages of the present invention that mixtures of these compounds, while sufliciently persistent to accomplish the desired effect upon the soil and upon the soil inhabiting organisms, dissipate in a reasonable period of time. Still another advantage is that mixtures of these compounds permeate soil for a distance of several inches from the point of application depending upon the temperature, organic content, moisture content, compactness and physical consistency of the soil or growth media.

In-carrying out the improved agronomic practice of the invention, the ethylene dibromide and 1,2-dibromo-3- chloropropane may be mixed together and such mixtures employed directly for-the treatment of soil. However, the present invention also embraces the employment of gaseous, liquid or dust compositions containing themixture of toxicants and for any fumigant purpose where the composition is valuable. Thus, the mixture of toxicants may be dissolved together in a suitable liquid carrier to provide compositions adapted to be distributed in soil. Such-liquid composition may also be employed to furnigate the surfaces of certain fruits, vegetables and grains where the products tolerate the fumigation action. Similarly, the ethylene dibromide and 1,2-dibromo-3- chloropropane may be dispersed together on or in a granular or finely divided solid carrier to provide compositions adapted to be distributed in soil or employed as concentrates and subsequently diluted with additionalinert carrier to produce the ultimate treating compositions. In a further mode of operation, the ethylene dibromide and l,2-dibromo-3-chloropropane may be blended with a suitable surface-active dispersing agent with or without one or-more liquid carriers to provide concentrates suitable for dispersion in water to prepare soil treating compositions in theform of aqueous dispersions or emulsions.

The compositions of the invention may be prepared in any suitable fashion. Since the ethylene dibromide and l,2-dibromo-3-chl0ropropane compounds are miscible in all proportions, compositions without carriers may be prepared by simple mixing of the components atordinary temperatures. In the preparation of compositions containing a liquid organic carrier, the ethylene dibromide and 1,2-dibromo-3-chloropropane are thoroughly mixed in the'liquid organic carrier at ordinary temperatures. Suitable liquid organic carriers include liquid aliphatic and aromatic hydrocarbons such as toluene, xylenes, naphthas and hydrocarbon mixtures derived from the distillation of petroleum or coal. For some fumigation operations, such carriers as carbon tetrachloride or ethylene dichloride may be employed. In general, it is preferred to avoid liquid carriershaving such low flash points as to constitute a fire hazard or such high boilingpoints as to leave undesired residues after use of the compositions. Depending upon the concentration of the mixture of toxicants, such augmented compositions are adapted to be distributed inthesoil or otherwise, --or employed as concentrates and subsequently diluted with additional carrier to produce the ultimate treating compositions.

In a preferred embodiment of the invention, selected petroleum distillates are employed as liquid carriers. Petroleum distillates used in such embodiment are carefully fractionated portions boiling almost entirely under 400 F. at atmospheric pressure and-having a flash point above about F. Thesefumigantcompositionsare characterized by having excellent penetrating properties and by being of low fire hazard to the shipper and user.

In the preparation of dispersible concentrate compositions, the ethylene dibromide and 1,2-dibromo-3-chloropropane components are mixed together in the proportions previously set forth together with a surface-active dispersing agent soluble in the composition with or without the further addition of a liquid organic carrier. The surface-active agents are usually employed in the amount of from 1 to percent by weight of the combined weight .of the toxicant mixture and surface-active agent. Suitable surface-active dispersing agents include polyoxyalkylene derivatives of alcohols, phenols and organic acids, oil-soluble petroleum sulfonates and polyoxyethylene derivatives of glycerol, glycols and the like.

In compositions in which the ethylene dibromide and 1,2-dibromo-3-chloropropane components are dispersed on or in a granulated or finely divided solid carrier, said components may be added directly to the solid carrier with mechanical mixing. Alternatively, the components may be combined with one or more of the aforementioned liquid organic carriers and the resulting compositions admixed with the solid carrier. Suitable solid carriers include silica gel, woodflour, fullers earth, chalk or gypsum and the like.

In formulating the compositions, it is essential to maintain the proportions of from one part by weight of ethylene dibromide to from about three to ten parts by weight of l,2-dibromo-3-chloropropane and to provide an effective amount of said mixture in the finished composition in order to obtain the desired synergistic effect. The concentration of the mixture of toxicants in organic solvent compositions employed to supply the desired dosage is generally from about 10 to 85 percent by weight. With aqueous compositions, the required dosage is generally supplied with compositions containing from 1 to 50 percent, although concentrations of 0.0002 percent by weight conveniently may be employed in irrigation treatments of soil. In compositions wherein the active mixture is dispersed on the solid carrier, it is generally desirable to employ from about 1 to about percent by weight of the above mixture of active ingredients in the finished solid compositions. With high capacity carriers, such as silica gel, the active ingredients may amount to percent by weight or more of the solid composition. In any case, it is desirable to employ suflicient of the solid carrier so that the liquid composition is adsorbed or absorbed to provide a freeflowing solid mixture. In compositions to be employed as concentrates, the toxicant mixture oftentimes is present in a concentration of from about 5 to 95 percent by weight.

The soil may be treated with the toxicant mixture or a composition containing the mixture of toxicants in any suitable fashion. With liquid compositions, good results have been obtained by depositing the active fumigant mixture at regular intervals beneath the surface of the soil. Such deposition may be accomplished readily by automatic machinery or by hand-operated apparatus. Thus, the active composition may be sprayed or otherwise deposited in a furrow which is subsequently closed to keep the active agents in the desired zone of the soil to be treated. Alternatively, the liquid compositions may be injected into the soil at predetermined intervals. In any case, the active composition is usually deposited at a depth of from about 4 to 18 inches below the soil surface.

In row treatments it is advantageous to place the fumigant composition at least 12 inches below the surface of the seed bed and to seal in the fumigant by listing the soil or by other suitable means such as ring rollers or press sealers attached behind the applicator. In overall applications with chisel-type applicators, the fumigant composition may be applied in uniform treatments 1 to 12 inches apart at a depth of 6 to 8 inches. With plow-sole applications, it is desirable to employ about 8 inches spacing between the furrows and to spray or otherwise introduce the fumigant composition so as to cover the bottom of the furrow. Where injection of the active composition at intervlas is employed, good results are obtained when injecting at intervals of from 3 to about 12 inches, although somewhat greater intervals may be employed in certain cases. In the above operations, it is desirabie to apply the fumigant composition after the soil has been worked into seed bed condition and when the soil temperature is above 50 F. and the soil moisture content is suflicient for seed germination.

In another mode of operation, the fumigant composition in emulsifiable form may be dispersed in water employed to irrigate the soil. In this method, the amount of water may be varied in accordance with the porosity and water-holding capacity of the soil in order to obtain the desired depth of distribution of the toxicant mixture.

The amounts of the ethylene dibromide and 1,2-dibromo-3-chloropropane composition to be employed will vary depending upon such factors as the type and condition of the soil, the varieties and growth stages of soil pests to be controlled and the particular crop to be planted thereafter. The essential criterion is to employ an amount for accomplishing the desired effect upon the soil-dwelling invertebrate organisms and the plant growing properties of the soil. Ingeneral, good results are obtained when the mixture of toxicants is distributed in growth media to a depth of from 4 to 12 inches at a dosage of at least one pound per acre. In field applications, the mixture of toxicants is usually introduced into the soil at a depth of about 6 inches and at a dosage of from 1 to 50 pounds per acre. Where compositions embodying a liquid or solid carrier are used, the amount of composition is adjusted to distribute substantially the above-described amounts of the active toxicant mixture per acre. The required amount of the toxicant mixture in the soil conveniently may be supplied per acre treated in from about 10 to gallons of organic solvent carrier, in from 10 to 162,000 gallons or more of the aqueous carrier or in from about 50 to 1,000 pounds or more of the solid carrier.

In one embodiment of the invention, the treated soil is planted with the desired crop plant following the distribution of the toxicant compounds in the soil. Where minimum dosages of the toxicant compounds are distributed in soil, the treated soil may be immediately planted with the desired crop. Following the distribution of larger dosages of the toxicant compounds, it is desirable that any planting operation not be carried out for a period of from several hours to several days, the exact period depending upon the concentration of the toxicant compounds in the soil and the resistance of the species concerned to the compound. Where the mixture of toxicant compounds is employed for the treatment of the soil adjacent to the root system of established plants having resistance to the compounds and in side-dressing operations, the existing vegetation is not unfavorably affected by minimum efiective concentrations of the toxicant compounds temporarily present in the soil.

The following examples illustrate the invention but are not to be construed as limiting:

EXAMPLE 1 Amount of toxicant in grams per liter of acetone Composition 1,241tbromoa-chloropropane Ethylene dibromide serene? These compositions were employed for the treatment of sandy loam soil heavily infested with root-knot nematodes. In such operations, the soil was placed in sealable containers and thereafter treated with the, compositions by injection to give various dosages of toxicant per acre foot of soil. The containers of treated soil were then sealed and set aside for one week. Containers of untreated soil were similarly sealed and set aside to serve as checks.

Following the latter period, the containers were unsealed and the soil allowed. to aerate for one week and thereafter planted with tomato seeds. During the subsequent growing period, there was observed no adverse effect upon the growth ofthe seedlings attributable to the presence of residual toxicant. About 7 weeks after planting, the plants were lifted from the soil and the roots washed and examined for gall formation due to nematode attack. The results obtained together with the dosages at which the toxicants were employed are set forth in the following table:

In the check plots which received no treatment, the plants were dwarfed and their roots heavily covered with galls attributable to nematode attack.

EXAMPLE 2 1,2-dibromo-3-chloropropane and ethylene dibromide were dissolved in acetone to produce the following compositions:

Amount of toxicant in grams per liter of acetone Composition l,2-dibromo- Ethylene 3-chlorodibromide propane These compositions were employed for the treatment of sandy loam soil heavily infested with root-knot nematodes. In such operations, the soil was placed in sealable containers and thereafter treated with the compositions by injection to give various dosages of toxicant per acre foot of soil. The containers of treated soil were then sealed and set aside for one week. Containers of untreated soil were similarly sealed and set aside to serve as checks.

Following the latter period, the containers were unsealed and the soil allowed to aerate for one week and thereafter planted with tomato seeds. During the subsequentgrowing period, there was observed no adverse effect upon the growth of the seedlings attributable to the presence of residual toxicant. About 7 weeks after planting, the plants were lifted from the soil and the roots washed and examined for gall formation due to nematode attack. The results obtained together with the dosages at which the toxicants were employed are set forth in the following table:

Dosage 01 toxicant in pounds per acre foot of soil Percent Composition control of nemal,2-dibr0mo- Ethylene todes 3-chl0rodibromide propane In the check plots which received no treatment, the plants were dwarfed and their roots covered with galls attributable to nematode attack.

EXAMPLE 3 Composition A Fifty-five parts by weight of 1,2-dibromo-3-chloropropane, 15 parts of ethylene dibromide, 27 parts of xylene and 3 parts of a dimeric alkylated aryl polyether alcohol (Triton X-l55) are mixed together to prepare a concentrate composition in the form of an emulsifiable liquid.

Composition B in a further operation, 50 parts by weight of 1,2-dibromo-3-chloropropane, 15 parts of ethylene dibromide, 33 parts of xylene and 2 parts of an alkyl aryl sulfonate (Nacconal NR) are mechanically mixed together to produce a water-dispersible concentrate composition.

Composition C Composition D In an additional operation, l,2-dibromo-3-chloropropane and ethylene dibromide are dissolved in Standard Thinner 250 to produce a fumigant composition containing 26 percent by weight of l,2-dibromo-3-chloropropane and 8 percent by weight of ethylene dibromide. Standard Thinner 250 is a petroleum hydrocarbon fraction boiling at from 192 to 272 F.

The concentrate compositions as above described are adapted to be dispersed in water to produce aqueous compositions having very desirable wetting and penetrating properties. The latter aqueous compositions and the above described solvent fumigant compositions are adapted to be employed to treat soil and to distribute the mixture of toxicants therein in effective concentrations.

EXAMPLE 4 Composition A as prepared in Example 3 is dispersed in water to produce a composition containing 25 pounds of the mixture of toxicants per 200 gallons of ultimate mixture. This composition, while under agitation, is metered into irrigation water at the pump outlet at the rate of 2 gallons per 1,000 gallons of irrigation water. The water is in a state of turbulent flow as it comes from the pump which provides for the thorough mixing of the toxicants therein. About 2 acre inches of irrigation water is applied per acre to land heavily infested with wire worms and root-knot nematodes to accomplish a wetting of the soil to a depth of about 12 inches. Two weeks after the treatment, the soil is planted with tomatoes. In a check operation, adjacent but similarly infested soil is also planted with tomatoes. Eight weeks after seeding, the plots are inspected and representative plants lifted from the soil and their roots examined for evidence of wire worm and nematode attack. The examination indicates a commercial control of both soil organisms in the treated soil with severe infestation in the check plots.

We claim:

1. A fumigant composition comprising as active toxic ingredients from about 1 part by Weight of ethylene dibromide and from about 3 to 10 parts by weight of 1,2- dibromo-3-chloropropane, the active toxic ingredients of said composition being mutually activating. 2. A fumigant composition comprising a carrier and dispersed therein as ac 've toxic ingredients from about 1 part by weight of ethylene dibromide and from about 3 to 10 parts by weight of 1,2-dibromo-3-chloropropane, the active toxic ingredients of said composition being mutually activating.

3. A composition comprising as active toxic ingredients from about 1 part by weight of ethylene dibromide and from about 3 to 10 parts by weight of 1,2-dibromo-3- chloropropane in intimate admixture with an adjuvant selected from the group consisting of (A) finely divided inert solids, (B) emulsifying and dispersing agents, and (C) petroleum distillates, the amount of such :adjuvants employed in the compositions being from 70 to 99 percent by weight for (A), from 1 to 20 percent by weight for (B), and from 15 to 90 percent by weight for (C).

4. A composition claimed in claim 3 wherein the active toxic ingredients are admixed with a finely divided inert solid.

5. A composition claimed in claim 3 wherein the active toxic ingredients are admixed with a petroleum distillate.

6. A composition claimed in claim 3 wherein the active toxic ingredients are admixed with a surface-active dispersing agent.

. 7. Afumigant composition which comprises an aqueous dispersion of the composition claimed in claim 6, the mixture of active toxic ingredients being present in the amount of at least 0.0002 percent by weight.

8. In the practice of agricultural economy, the method Which comprises impregnating soil with a parasiticidal dosage of a composition comprising from about 1 part by weight of ethylene dibromide and from about 3 to 10 parts by weight of 1,2-dibromo-3-chloropropane.

9. In the practice of agricultural economy, the method which comprises impregnating soil with a parasiticidal dosage of a composition comprising as active toxic ingredients from about 1 part by weight of ethylene dibromide and from about 3 to 10 parts by weight of 1,2- dibromo-3-chloropropane in intimate admixture with a petroleum distillate.

References Cited in the file of this patent UNITED STATES PATENTS Dawson Aug. 12, 1952 OTHER REFERENCES 

1. A FUMIGANT COMPOSITION COMPRISING AS ACTIVE TOXIC INGREDIENTS FROM ABOUT 1 PART BY WEIGHT OF ETHYLENE DIBROMIDE AND FROM ABOUT 3 TO 10 PARTS BY WEIGHT OF 1,2DIBROMO-3-CHLOROPROPANE, THE ACTIVE TOXIC INGREDIENTS OF SAID COMPOSITION BEING MUTUALLY ACTIVATING. 